Construction and Comprehensive Analysis of a Competitive Endogenous RNA Network and Potential Regulatory Axes in Gastric Cancer

Background: Long non-coding RNAs (lncRNAs) have been identified as micro RNA (miRNA) sponges in a competing endogenous RNA (ceRNA) network, and are involved in the regulation of gene expression. This study aims to construct a lncRNA-associated ceRNA network in GC. Methods: Differentially expressed lncRNAs, mRNAs, and miRNAs were identified by analyzing the expression profiles of GC retrieved from The Cancer Genome Atlas (TCGA) database. The lncRNA-miRNA-mRNA regulatory networks of GC were constructed by comprehensive bioinformatics methods including functional annotation, RNA-RNA interactomes prediction, correlation analysis, and survival analysis. The interactions and correlations among ceRNAs were validated by experiments on cancer tissues and cell lines. Results: A total of 41 lncRNAs, 9 miRNAs, and 10 mRNAs were identified and selected to establish the ceRNA regulatory network of GC. Several ceRNA regulatory axes, which consist of 18 lncRNAs, 4 miRNAs, and 6 mRNAs, were obtained from the network. A potential ADAMTS9-AS2/miR-372/CADM2 axis which perfectly conformed to the ceRNA theory was further analyzed. qRT-PCR revealed that ADAMTS9-AS2 knockdown significantly increased miR-372 expression but reduced CADM2 expression, while ADAMTS9-AS2 overexpression had the opposite effects. Dual luciferase reporter assay indicated that miR-372 could bound to the ADAMTS9-AS2 and the 3'UTR of CADM2. Conclusions: The constructed novel ceRNA network and the potential regulatory axes might provide a comprehensive understanding of the potential mechanisms of development in GC. The ADAMTS9-AS2/miR-372/CADM2 axis could serve as a potential therapeutic target for GC treatment. Funding Statement: This study was supported by Beijing Natural Science Foundation (7184240). Declaration of Interests: The authors declare: "None." Ethics Approval Statement: Written informed consent was obtained from all patients. This study was performed with the approval of the Ethics Committee of the Beijing Hospital.